README.md

nodemon

nodemon will watch the files in the directory in which nodemon was started, and if any files change, nodemon will automatically restart your node application.

nodemon does not require any changes to your code or method of development. nodemon simply wraps your node application and keeps an eye on any files that have changed. Remember that nodemon is a replacement wrapper for node, think of it as replacing the word "node" on the command line when you run your script.

Automatic re-running

nodemon was originally written to restart hanging processes such as web servers, but now supports apps that cleanly exit. If your script exits cleanly, nodemon will continue to monitor the directory (or directories) and restart the script if there are any changes.

Manual restarting

Whilst nodemon is running, if you need to manually restart your application, instead of stopping and restart nodemon, you can simply type rs with a carriage return, and nodemon will restart your process.

Config files

nodemon supports local and global configuration files. These are named nodemon.json and can be located in the current working directory or in your home directory.

The specificity is as follows, so that a command line argument will always override the config file settings:

command line arguments

local config

global config

A config file can take any of the command line arguments as JSON key values, for example:

The above nodemon.json file might be my global config so that I have support for ruby files and processing files, and I can simply run nodemon demo.pde and nodemon will automatically know how to run the script even though out of the box support for processing scripts.

Using nodemon as a module

Running non-node scripts

nodemon can also be used to execute and monitor other programs. nodemon will read the file extension of the script being run and monitor that extension instead of .js if there's no .nodemonignore:

nodemon --exec "python -v" ./app.py

Now nodemon will run app.py with python in verbose mode (note that if you're not passing args to the exec program, you don't need the quotes), and look for new or modified files with the .py extension.

Default executables

Using the nodemon.json config file, you can define your own default executables using the execMap property. This is particularly useful if you're working with a language that isn't supported by default by nodemon.

To add support for nodemon to know about the .pl extension (for Perl), the nodemon.json file would add:

{
"execMap": {
"pl": "perl"
}
}

Now running the following, nodemon will know to use perl as the executable:

nodemon script.pl

It's generally recommended to use the global nodemon.json to add your own execMap options. However, if there's a common default that's missing, this can be merged in to the project so that nodemon supports it by default, by changing default.js and sending a pull request.

Monitoring multiple directories

By default nodemon monitors the current working directory. If you want to take control of that option, use the --watch option to add specific paths:

nodemon --watch app --watch libs app/server.js

Now nodemon will only restart if there are changes in the ./app or ./libs directory. By default nodemon will traverse sub-directories, so there's no need in explicitly including sub-directories.

Specifying extension watch list

By default, nodemon looks for files with the .js, .coffee, and .litcoffee extensions. If you use the --exec option and monitor app.py nodemon will monitor files with the extension of .py. However, you can specify your own list with the -e (or --ext) switch like so:

nodemon -e js,jade

Now nodemon will restart on any changes to files in the directory (or subdirectories) with the extensions .js, .jade.

Ignoring files

By default, nodemon will only restart when a .js JavaScript file changes. In some cases you will want to ignore some specific files, directories or file patterns, to prevent nodemon from prematurely restarting your application.

This can be done via the command line:

nodemon --ignore lib/ --ignore tests/

Or specific files can be ignored:

nodemon --ignore lib/app.js

Patterns can also be ignored (but be sure to quote the arguments):

nodemon --ignore 'lib/*.js'

Note that by default, nodemon will ignore the .git, node_modules, bower_components and .sass-cache directories.

Delaying restarting

In some situations, you may want to wait until a number of files have changed. The timeout before checking for new file changes is 1 second. If you're uploading a number of files and it's taking some number of seconds, this could cause your app to restart multiple times unnecessarily.

To add an extra throttle, or delay restarting, use the --delay command:

nodemon --delay 10 server.js

For more precision, milliseconds can be specified. Either as a float:

nodemon --delay 2.5 server.js

Or using the time specifier (ms):

nodemon --delay 2500ms server.js

The delay figure is number of seconds (or milliseconds, if specified) to delay before restarting. So nodemon will only restart your app the given number of seconds after the last file change.

Controlling shutdown of your script

nodemon sends a kill signal to your application when it sees a file update. If you need to clean up on shutdown inside your script you can capture the kill signal and handle it yourself.

The following example will listen once for the SIGUSR2 signal (used by nodemon to restart), run the clean up process and then kill itself for nodemon to continue control: